Screw-cutting lathe.



No. 806,996. PATENTED DEC. 12, 1905. A. SCHUERMANN.

SCREW CUTTING LATHE.

APPLICATION FILED JUNEIO, 1905.

4 SHEETS-SHEET l.

No. 806,996. v PATENTED DEC. 12, 1905. A. SGHUBRMANN.

SCREW CUTTING LATHE.

KPPLIGPJI'ION IILED JUNE 10, 1905.

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Inventor.

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PATENTED DEC. 12, 1905. A. SGHUERMANN. SCREW CUTTING LATHE.

APPLIOATION FILED JUNE 10, 1905.

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A. SGHUERMANN.

SCREW CUTTING LATHE.

APPLIOATION FILED JUNE 10, 1905.

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Inventor,

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ANTON SOHUERMANN, OF DECATUR, ILLINOIS, ASSIGNOR OFONE-HALF TO H.MUELLER MANUFACTURING COMPANY, OF DECATUR, ILLINOIS,

A CORPORATION OF ILLINOIS.

Specification of Letters Patent.

Patented Dec. 12, 1905.

' Application filed June 10, 1905. Serial No. 264,724.

To all whom, it may concern:

Be it known that I, ANTON SCHUERMANN, of the city of Decatur, county ofMacon, and State of Illinois, have invented certain new and usefulImprovements in Screw-Cutting Lathes, of which the following is aspecification.

The object of this invention is to provide means whereby thethread-cutting tool may be moved slightly faster or slightly slower thanthe regular motion of the tool-rest, so that the lathe may be used foreither inch measure or metric measure and so that shrinkage of cutthreads through tempering or otherwise may be compensated for oranticipated. For instance, a tap intended to cut threads of a certainpitch maybe threaded by my machine to the slightly increased pitchneeded to neutralize or compensate for the shrinkage resulting fromsubsequent tempering, or bolts or the like may be threaded to theslightly-reduced pitch needed to conform to holes threaded by taps thethreads of which have been shrunk from regular size by tempering.

The mechanism herein described may be applicable to purposes notspecifically stated, and it is my desire to patent the invention for allpurposes to which it may be applied.

The invention is exemplified in the structure hereinafter described, andit is defined in the appended claims.

In the drawings forming part of this specification, Figure l is anelevation of so much of a screw-cutting lathe as is needed to show therelation of my invention thereto. Fig. 2 is a plan of the mechanismshown in Fig. 1. Fig. 3 is a side elevation of an embodiment of myinvention detached from the lathe-can riage. Figs. 4 and 5 are plandetails of certain parts of my machine, showing how the motion thatretards or accelerates the cutting-tool is developed by travel of thesliderest through inclined-plane action. Fig. 6 is a detail plan of theslotted bar and adjuncts used in developing the variable-speed movement.Fig. 7 is a plan of the under surface of that part of the slide-restthat is accelerated or delayed to vary the pitch of the,

threads. Fig. 8 is a detail of the elements that coact with the slottedbar to develop the variable motion in the cutting-tool. Fig. 9

is a detail of the under surface of the dial plate, which receivesmotion from the slotted bar through the elements shown in Fig. 8 andimparts it to the tool-carrying part of the slide-rest. Figs. 10 and 11are plans of my invention, illustrating the action thereof.

Fig. 12 is a plan of the upper element of the slide-rest with thedial-platein place. Fig. 13 is a similar plan with the dial-plateremoved. Fig. 14 is a section on lineX in Fig. 13'. Fig. 15 is a sectionon line X in Fig. 12. Fig. 16 is a detail in elevation of the dialplateand the parts that coact most intimately therewith.

A slide-rest is formed in two parts 14 and 18. The part 14 is secured tothe cross-slide 20 of a tool-carriage of a screw-cutting lathe by boltsextending through holes 15, and it occupies the same position as a.compound swivel-rest. A bar 19 is secured to the tailstock 21 of thelathe, and it extends horizontally crosswise of the lathe, with an edgepresented upward. A flat bar 1 is grooved crosswise at one end in itsunder surface to engage bar 19, as shown in Fig. 1, and it has theoblique groove 2 in its upper surface. A key 3 fits slidably in groove2. A plate 4 is formed on the upper surface of the key crosswisethereof, and a pivot-pin 5 extends up ward from the center of plate 4. Aslide-key 6 is pivoted on pin 5, and it moves in groove 8 of the lowermember of the dial-plate. The part 14 of the slide-rest has the gib 14*,which fits slidably in the dovetail groove 18 of part 18 of theslide-rest, and the grooved bar 1 extends slidably lengthwise throughthe gib. A pair of cover-plates 16 are secured to the gib above thegrooved bar on opposite sides of the center of the gib, thus leaving across wise travel-space for the slide-plate 4. The upper part 18 of theslide-rest is recessed circularly immediately above the gib, as shown at18 in Fig. 14, is also recessed circularly in itsupper surface, as shownat 18 is bored centrally of the recesses, as shown at 18, and

is slotted, as shown at 18 A two-part dialplate is used to control theinclination of the pivoted slide-key 6, and this dial-plate is securedto part 18 of the sliderest, with the groove 8 receiving'the key. Theupper member 10 of the dial-plate occupies recess 18 and the lowermember 7 occupies recess 18*. A pivot extension 9 is formed on the uppersurface of member 7, and it pivots in bore 18 The extension 9 is boredand internally threaded, and the u per member 10 has an externallythreadecT extension 12, which screws into pivot extension 9. Awrenchseat 11 is formed on the upper surface of member 10, and a screw13 extends through a hole in the upper member, extends through slot 18in the slide-rest member, and screws into the lower dial-plate member'7. The dial-plate members are bored centrally, as shown in Fig. 15, toprovide an oil-passage leading to the slide-keys.

The upper part of the dial-plate is suitably graduated, as suggested inthe drawings, and the screw 13 holds the groove in the lower part of thedial-plate in proper relation to the gradations. The screw 13 alsoprevents the dial-plate from swinging slide-key 6 into an inoperativeposition by striking sides of slot 18", and it is used to clamp theparts of the plate onto the slide-rest, with the groove 8 extending inany desired direction.

When the dial-plate is fastened in the posi tion shown in Fig. 12, thepivoting slide-key 6 will be held at right angles with the slotted bar1, and the device will be inoperative or passive as an accelerator orretarder. When the dial plate is adjusted to the position shown in Figs.10 and 11, the slide-key 6 will be swung to the position shown in Figs.4 and 5, and under these conditions the upper part 18 of the slide-restwill advance with relation to the under part 14 to the extent shown inFigs. 10 and 11 as the tool-carriage is moved from one end of itsslideway to the other. By turning the dial-plate in the contrarydirection the slide-key 6 will be inclined, as shown in Fig. 8, and thetool-carrying part of the slide-rest will be retarded to an extent equalto the advance shown in Figs. 10 and 11. In the conditions abovementioned the set-screw 13 is supposed to be swung to one end or theother of slot 18' or to be located at the center of the slot but thedial-plate may be adjusted in various intermediary positions and thecutting-tool be accelerated or retarded to any required degree.

As the slide-rest moves along the grooved bar 1 the slide-key 3 followsthe inclination of groove 2 and moves plate 4 crosswise of,

the slide-rest or crosswise of the direction of the motion thereof. Theslide-key 6 travels with the plate 4 across the slide-rest, and when itis set obliquely it forms an inclined plane to convert its crosswisemotion into independent motion of part 18 of the sliderest lengthwise ofthe slotted bar. The mothe slotted bar 1 will slide on bar 19 to permitthis movement.

The set-screw 18 is loosened preparatory to adjusting the dial plate,the plate is turned to the required position by means of a wrenchapplied to seat 11, and the set-screw is retightened.

I claim as new and desire to secure by Letters Patent- 1. In ascrew-cutting lathe, the combination of a slide-rest member attached tothe carriage, a second slide-rest member movable on the first lengthwiseof the lathe and carrying a screw-cutting tool, a plate in the firstslide-rest member slidable crosswise thereof, a bar extended alongtheline of travel of the slide-rest and provided with an oblique groove,a slide-key fixed on the plate in engagement with the oblique groove, aslidekey pivoted on the plate, and an adjustable dial-plate on thetool-carrying member of the slide-rest having a groove in which thepivoted slide-key slides.

2. In a screw-cutting lathe, the combination of a slide-rest memberattached to the carriage, a second slide-rest member movable on thefirst lengthwise of the lathe and carrying a screw-cutting tool, a plateon the first slide-rest member slidable crosswise thereof, a barattached to the tail-stock crosswise of the lathe, a flat bar groovedcrosswise of one of its ends to slidably engage the bar on thetail-stock, and also having a groove extending obliquely along itslength, a fixed slide-key on the cross-plate engaging the oblique slotof the slotted bar, a slide-key pivoted on the cross-plate, and anadjustable dial-plate on the tool-carrying member of the slide-rest,having a groove in which the pivoted slide-key slides.

3. In a screw-cutting lathe, the combination of a slide-rest memberattached to the carriage and having a gib on its upper surface extendedlengthwise of the lathe, a bar fitted slidably in the gib lengthwisethereof, said bar being provided with an oblique groove in its uppersurface and held against lengthwise motion, a toolcarrying slide-restmember mounted slidably lengthwise of the lathe on the gibbed member, aplate having motion in the tool-rest crosswise of the travel thereof, aslide-key fixed on the under side of the cross-plate in engagement withthe slot of the bar, aslide-key pivoted on the cross-plate, a grooveddial-plate engaging the pivoted slide-key, and means for holding thedialplate in yarious positions.

In testimony whereof I sign my name in the presence of two subscribingwitnesses.

ANTON SCHUERMANN.

\Vitnesses:

ANNA MURPHY, JOHN L. VVADDELL.

IIO

